Known ω3 polyunsaturated fatty acids (hereinafter abbreviated as ω3PUFA) include α-linolenic acid, eicosapentaenoic acid (hereinafter abbreviated as EPA), and docosahexaenoic acid (hereinafter abbreviated as DHA). Since ω3PUFA and pharmaceutically acceptable salts and esters thereof have various actions such as anti-arteriosclerosis action, platelet aggregation suppressive action, blood lipid lowering action, anti-inflammatory action, carcinostatic action, and central action, they are blended in various food products, and commercially sold in the form of health food and medical and pharmaceutical products.
Ethyl eicosapentaenoate ester (hereinafter abbreviated as EPA-E) is commercially sold as an oral therapeutic agent for ameliorating ulcer, pain, and coldness associated with arteriosclerosis obliterans as well as hyperlipidemia (product name Epadel, Mochida Pharmaceutical Co., Ltd.). When EPA-E is administered orally under fasting, increase in plasma EPA concentration is smaller than the case of the oral administration after the meal conceivably because absorption of the EPA-E requires secretion of bile acid and food components as a carrier. Accordingly, Epadel is instructed to be orally administered three times a day each time immediately after the meal (see Non-Patent Literature 1).
However, dosage method or drug compliance has become a problem for those people not taking meals three times a day with the recent change in the life style, patients who can only take meals at a reduced amount, patients who can only take a fluid diet (milk, rice broth, starch gruel, egg, soup, juice, or oral nutritional supplement), patients with reduced absorption ability of the intestinal tract (for example, elderly, patients of intestinal disease, patients after intestinal surgery, terminal cancer patients, and patients taking a lipase inhibitor), or patients who are unable to take meals such as those after the cerebral infarction.
Recently, attention is paid to the relation between non-fasting hypertriglyceridemia, namely the condition in which serum triglyceride (hereinafter abbreviated as TG) is at its normal value under fasting while abnormally increased serum TG value is observed after taking meal or for a prolonged period after taking the meal and coronary artery disease (see Non-Patent Literature 2), and one cause which may be associated with this relation is enhancement of sterol regulatory element binding protein 1c (hereinafter abbreviated as SREBP1c). Prevention and improvement of lipotoxicity of pancreas β cell under the load of palmitic acid by continuous oral administration of the EPA-E under feeding has been reported, and involvement of the suppression of the SREBP1c in the mechanism has also been reported (see Non-Patent Literature 3). However, there is no report for the effectiveness of oral administration before the meal (under fasting), and an ω3PUFA preparation which is rapidly absorbed even if administered before the meal to suppresses increase of postprandial serum TG is highly awaited.
An emulsion composition containing an ω3PUFA, its pharmaceutically acceptable salt or ester exhibiting good processing and storage stability, which is gradually absorbed by oral administration and which exhibits prolonged absorption for a prolonged period has been reported (see Patent Literature 1). This composition comprises EPA-E and an emulsifier such as a polyglycerin fatty acid ester having a triglycerin content in polyglycerin of at least 60% or polyoxyethylene sorbitan fatty acid ester.
However, in the case of an emulsion preparation, content of the ω3PUFA, its pharmaceutically acceptable salt or ester which is the effective component is at most not more than several dozen percents, and moisture content is high. Accordingly, the entire amount of the preparation and the moisture that should be taken for the intake of a pharmaceutically effective amount is inevitably high, and administration of such amount is difficult for the patients such as dialysis patients whose water intake is limited, and the high water content means difficulty of capsulation in a capsule which is made of a material like gelatin. The high moisture content also results in the increase in the handling trouble and cost in the production, distribution, and storage.
A self-emulsifying preparation which does not contain water in the preparation and which is readily dispersible and self-emulsifying in water has been reported (see Patent Literature 2 and Non-Patent Literature 4). This preparation contains ω3PUFA and fenofibrate as its effective components, ethanol, and a surfactant.
Because of the inclusion of the ethanol in the composition, this composition is believed to suffer from the problems such as volatilization of the ethanol in the course of capsulation, and in particular, in the step of drying which invites increase in the risk of capsule deformation and bubble entrapment, volatilization of the ethanol in the course of distribution and storage which invites increase in the risk of capsule deformation and cracks, and denaturing and turbidity of the capsule content caused by the change in the composition due to the volatilization of the ethanol. Furthermore, such preparation including the ethanol can not be taken or such intake is difficult for the alcohol (ethanol) intolerant patients who suffer from face and systemic blush, increase in the heart and respiratory rates, as well as headache and vomiting by the small amount of alcohol intake due to the lack of aldehyde dehydrogenase which is an alcohol decomposition enzyme or the insufficient activity of the dehydrogenase. Such people genetically lacking the alcohol decomposition enzyme or those having low activity dehydrogenase are found in Mongoloids including Japanese at a high rate, and more specifically, in 40 to 45% of Japanese population, and in such a case, high ethanol content in the preparation should result in various disorders as apparent to those skilled in the art. For example, “Dictionary of Drug Additives (in Japanese)” discloses the maximum daily ethanol dose of 3.26 mg in the case of oral administration (see Non-Patent Literature 5).
In addition, there has so far been no report of the preparation which is less affected by meals and which can be administered to a patient who is unable to take meals or which can be orally administered to a patient under fasting such as a patient before going to bed; a preparation which can rapidly increase blood ω3PUFA concentration by the administration under fasting such as administration before the meal or before going to bed and which can rapidly and effectively realize the intended pharmacological action, for example, suppression of the increase of the postprandial serum TG; an ω3PUFA preparation which can be encapsulated in a gelatin capsule or the like and which can be used at a reduced volume; or a preparation with no or reduced ethanol content that have solved the ethanol-related problems as described above.